Pipe testing machine



Sept. 16, 1952 J HAHN I rm: ram-me mourns Filed Oct. 23, 1947 llwv M 4.57% M W ml/ xv k n m & J hwh w kfi & {mu

Sept. 16, 1952 J. HAHN PIPE TESTING MACHINE u .llv

Filed Oct. 23, 1947 Wm 5+ 8 'QQ. W NW NW WW. l/IAZZZaQI/l @W.

9 w. wm mm mm 0 mm :1 I, i! I 1 iii; 3 i

Patented Sept. 16 1952 .PIPE TESTING MACHINE Johann Hahn, Brooklyn, N. Y. i Application October 23, 1947, Serial No. 781,603

9 Claims. (Cl. 13890) The present invention relates to a novel pipe testing machine capable of simulating the pressure conditions to which pressure pipe is subjected in the field. 7

Conventional pipe testing machines are generally structures of considerable weight and of complicated design. The type of pipe testing machine most generally in use at the present time has two seats which are pressed against each end of the pipe to be tested. One seat is moved against the pipe by a number of hydraulically operated plungers, all or some of which, depending on the size of the pipe to be tested, may be activated. The other seat is held'against the other end of the pipe by tension rods which take up the reaction of the pipe against the seats. Suitable valves and orifices are provided to fill the pipe with testing water and to emptyit.

Pipe testing machines of this conventional type have a number of significant and'inherent disadvantages. The more important of these is due to the requirement'that the pipe'to be tested be placed under heavy longitudinal compressive The use of these plugassemolies enables the pipe section to be tested under exactly the same conditions as those encountered inthe field, although in a quantitative way these stresses may be multiplied. *Thus, for example, the pressure of the testing fluid within the pipe section during the test may be a multiple of that which the pipe -'During the test, however, thepipe section need stresses to secure adequate-sealingat the ends.

As a result of this requirement, the length of pipe section that can be tested is limited by its slenderness ratio, whichmust not be so great as to permit buckling stresses to be created. Furthermore, transverse cracks are-not permittedto develop or become noticeable because the force applied to the ends of the pipe section tends to close such cracks. Other important disadvantages of such machines are their high initial cost, great structural weight, immobility, and the difficulty of equalizing the pressures exerted by the pressure plungers against the movable seat.

In accordance with the present invention the two ends of a pipe section are sealed by independent plug assemblies having one or more elastic sealing rings pressed against the walls of the pipe section by a combination of mechanical force and fluid pressure. The construction of the plug assemblies is such that the force with which the sealing rings are pressed against the walls of the pipe section creates sufiicient friction between the rings and the walls to retain the plug assemblies in the pipe section against the longitudinal component of the fluid pressure within the pipe tending to expel the plug assemblies therefrom. The fluid pressure applied to the sealing rings is a direct-function of the fluid pressure in the pipe. Consequently, the frictional resistance of the plug assembly to expulsion from the pipe sectionincreases with an increase in fluid pressure. I

not be subjected to longitudinal compressive stresses that are not encountered in the field and hich would tend to minimize or eliminate'the detection of transverse flaws or cracks in the pipe.

One of the advantages of the present invention, therefore, is that it provides a machine for testing pipe sections under the kind of conditions to which they are subjected in actual use.

An ancillary advantage of the invention is that it provides a machine for testing pipesections in a manner that will reveal faults hitherto undetectable by conventionalpipe testing apparatus. r

A still further advantage is that it provides pipe testing apparatus that requires no foundation, such as of concrete orthe like, and therefore enables tests to be carried out in the field.

These and other advantages, as well as the utility of the invention, will become apparent from the'following description and from the accompanying figures of drawing wherein: I y Figure l is a View in longitudinal section through one portion'of'one embodiment of the pipe testing apparatus of this invention;

Figure 2 is a detailed section, on an enlarged scale, through section '22.of Figure 1 showing several cooperative elements of a plug assembly in position in a pipe section prior to the application of mechanical and fluid pressure;

Figure 3 is a similar detailed view showing the positions of the same elements afterthe application of machanical and fluid pressure;

Figure 4 is a view in horizontal elevation of a pipe testing set-up in accordance "with the pres ent invention;

Figure 5 is a sectional View taken along seotion line 5-5 of Figure 1 looking in the direction of the arrows; I

Figure 6 is a view through one portion of another embodiment of the pipe testing apparatus; and

Figure 'Iis a view in cross section taken along section line 1-4 of Figure 6 looking in the direction of the arrows.

' I Asshown in Figure Lea recessed plug member I0 having "a recess 12, a head l4, one or more in longitudinal section 3 radial fluid passageways l6 and a section l8 of reduced diameter, is adapted to flt within one end of a pipe section 20. The exterior end 2| of said plug member ID is threaded to receive a hub section 22 of a hand wheel 24. The interior end 26 of the hub section 22 bears against an annular follower 28 slideable longitudinally on the bearing portion 30 of the plug member [0. The follower 28 in turn bears against an annular pressure transmitting member 32 provided with one or more grooves.34. An annular sealing gasket 36 is provided between the follower 28, the pressure transmitting member 32, and the cylindrical surface 38 of the plug member ID.

The interior surface of the pressure transmitting member 32 is provided with a radial'grooved' portion 40. One or more annular, pressure transmitting members 42 of T-shape cross section having radial grooves 44 and longitudinal grooves 46 are provided around the plug member I8, as shown for example. in Figure l. A sealing ring 48 of resilient material, preferably having a high coefficient of static friction and preferably provided with rimrsections 50, is disposed between each two of the annular pressure transmitting members '42, between the outermost annular pressure transmitting member'42 and the pressure transmitting member "32 bearing against the follower 28, and between the innermost annular pressure transmitting member 42 and the head l4.

The recess [2 of the plug member [Bis provided with a discharge pipe 52 having an upstanding opening'54 adjacent the wall of the pipe section 28 and communicating by way of central passage 56 with a discharge pipe 58 provided with a hand valve 68.

The device inserted into the other end of the pipe section to be tested is similar in all'details except that the discharge pipe 58 can be eliminated and the central passage 56 is connected to a source of fluid pressure 62 as shown in Figure 4. If desired, an indicator arm 63 may be attached to one end of the pipe section to be tested so that the increase in length of the pipe section while under pressure may be measured on a scale 64 which may, if desired, be provided with a multiplying device.

In operation, the plug assembly including the plug member In, one or more resilient sealing rings 48, an appropriate number of annular pressure transmitting members 42, one annular pressure transmitting member 32, the follower 28, and the handwheel 24, is inserted into' each end of the pipe section to be tested. One of these I plug assemblies is provided with discharge pipes 52 and 58 and'a hand valve 60 and the other is connected to a source of fluid pressure 52. At this stage of the operation the relative positions of the plug assembly elements and the interior wall of the pipe section are substantially as shown in Figure 2.

Each handwheel 24 is then rotated so as to move hub section 22 inwardly toward the pipe section 20 with the result that the follower. 28 I section 28 and the rim sections of the sealing rings 48 are pressed against the upstanding flanges of the annular pressure transmitting members 32 and 42 and head [4 so as to form fluid tight seals therewith. The groove sections 40 and 44 of the pressure transmitting members 42 and 32, however, remain open and in communication with recess l2 by way of radial fluid passageways I6 and. longitudinal grooves 46.

When both plug assemblies have thus been inserted-into the ends ofthe pipesection 20, the

valve 66 communicating with source of fluid pressure 52 is opened so as to fill the pipe section 20 section may escape through discharge pipes 52 and 58. As soon as the fluid in the pipe section 20- completely fills the pipe section it will begin to be discharged through discharge pipe 58 whereupon the discharge valve is closed. The valve 66 is then left open until the desired fluid pressure .is attained withinthe pipe section 20 whereupon it likewise maybe closed.

The force of the fluid pressure within the pipe section tending to push the plug. assemblies out of the ends of the pipe section isutilizedto more firmly retain saidassemblies. therein. The fluid pressure passes through fluid passageways l8 and the fluid passageways formedbygrooves 40,.44, and 46, to bear againstthe inneresurfaces flof the resilient sealing rings48. toflthusincrease the pressure betweenthe sealingringsand .the interior surface of the pipe section. .since nocompressive stresses are .exertedragainst the opposite ends of the pipe section 28,. it is free=.to. extend in a longitudin'aldirection and therebyto. expose and render detachable transverseas well'as longitudinal flaws 'inthepipe. .This also. makesit possible to measure 'the elongation-of thepipe section under a, predetermined. fluid pressure.

The modification illustrated in Figures 6- and- 7 operates on the same principle .as thatdescribed with reference to the modification illustratedin Figures 1 to 5. Theplug memberlflafitting within the pipesection 20, theresilient sea-ling rings 48, and the annular pressure transmitting members 32 and 42 are substantiallysimilar to those described previously. ,The hub. section 10 of the handwheel 24, however, isof -a simple flange type wherein the flange'fllbears'against=.a plurality of compression bars "l4 .which, .pass through and are longitudinally 'movable'within an annularghousing '16. The compressionbarsr in turn bear against an annular follower,80,:'recessed at 82 to-accommodate.thethickness oi the pipe wall, and said followeri.88;in;turn:bears against exterior. and interior annular-spressure transmitting members; 32zand: 84:.-respectively. A resilient sealing; ring 86,. similar in icrosssection to the sealing rings 48 'insideithespipe section 'is disposed between each ofthe annularrpressure transmitting members .88,'betweenzannular 'pressure transmitting. members 1 84;:ands88; and between the innermostannular pressure. transmitting member' 88 and an external head 88 suitably bolted to the inner end of .the annularrhousing 16 by means of bolts92 or the like. 'F'Ihepressnre transmitting members .84 :and:.-:88 andltheifollower are provided with groove:sections'94, 85, and 96, communicating withradialz'grooves. mm the plug member Illa.

Sealing gaskets 98 are provided.-around the openings in the outer'end of .theannular housing 16 through-which the compressiombarsz14rpass and a nut 18 may be provided toassistzhrrethining the housing 16 and theplug'memberlloa in their relative positions. i a

In operation, a plug assembly such as that illustrated in Figures 6 and 7 is inserted into each end of the pipe to be tested. When this apparatus is in place the handwheel 24 is turned until the various pressure transmitting members become locked. In this position, as in that shown in Figure 3, each of the resilient sealing rings48 and 86 is forced, by mechanical pressure, against the inner or outer wall, respectively, of the pipe section. When fluid pressure is applied to the interior of the pipe section in the manner described previously, it is transmitted to each of the resilient sealing rings 48 and'llfi by way of radial passageways l6 and 44, longitudinal passageways 46, 94, 95 and 95, and the recess in the annular housing 16.; 1

It is to beunderstood that innumerable alterations and modifications will occur tothose skilled in the art upon reading the-foregoing description of the invention. Thus, for example, the number of resilient sealing rings, their relative width, their precise cross section, the shape of the annular pressure transmitting members, the details of construction of the plug assemblies, the arrangement for the application of fluid pressure, the manner of measuring the elongation of the pipe section while under pressure, and many other details may be altered considerably without departing from the principles of this invention. It is to be understood, therefore, *that'all such modifications and alterations, of which the fore-. going are only a'few, come withinthe scope of the invention as defined in the following claims.

I claim:

1. A plug assembly for testing pipes under fluid pressure comprising a plug member adapted to fit within a pipe section, said member having a head and a pasageway open at one end to fluid within said pipe section, an annular housing attached to said plug member at one end and spaced therefrom throughout most of its length, said housing being provided with a separate head,

a plurality of inner annular pressure transmitting members disposed around said plug member and adapted to fit within said pipe section, resilient sealing rings having inwardly projecting rim sections and disposed around said plug member and in alternate series with said inner pressure transmitting members, a plurality of outer annular pressure transmitting members disposed within said housing and adapted to flt around said pipe section, resilient outer sealing rings having outwardly projecting rim sections disposed within said housing and in alternate series with said outer pressure transmitting members, means for moving said inner and outer pressure transmitting members toward said heads to cause the pressure members to press against said rim sections and deform the sealing rings and press them against the interior and exterior walls of said pipe section, said passageway being adapted to transmit fluid pressure within said pipe section to said sealing rings to supplement the pressure thereof against the walls of the pipe section, and a closable opening in said plug member for the passage of fluid therethrough.

2. A plug assembly for testing pipes under fluid pressure comprising a plug member adapted to fit within a pipe section, said member having a head and a passageway open at one end to fluid within said pipe section, a plurality of annular pressure transmitting members disposed around said plug member and adapted to flt within pipe section. I

6 said pipe. section, resilient. sealing rings disposed around said plug member and in alternate series with 'said pressure transmitting- ;ner wall'ofjthe pipe section.

3. A plug assembly for testing pipes under fluid pressure comprising a plug member adapted to fit within a pipe section, said member having a head at one end, a plurality of annular pressure transmitting members disposed around said plug member and adapted to fit within said pipe section, resilient sealing rings disposed around said 'plug member andin alternate series with said pressure transmitting members, andmeans for moving said pressure members toward said head to deformqthe sealing ringsand press their outer surfaces against the interior wall of the pipe section, and a passageway insaid plug member communicating with the inner'surfaceof said rings to transmit fluid pressure within said pipe section to said sealing rings to'supplement the pressure thereof against the inner wall of said 4. A plug assembly for testing pipes under fluid pressure comprising a plug member'adapted to pipe section, resilient sealing rings disposed around said plug member and in alternate series with said pressure transmitting members, and means for moving said pressure transmitting members toward said head to deform the sealing rings and press their outer surfaces against the interior wall of the pipe section, said passageway communicating with the inner surfacesof the sealingrings to trasmit fluid "pressure within said pipe section to the sealing rings to supple ment the pressure thereof against the interior wall of the pipe section.

5. A plug assembly for testing pipes under fluid pressure comprising a plug member including a housing having an open end adapted to fit around the end of a pipe section, said member having a head at the open end and a passageway open at one end to fluid within said pipe section, a plurality of annular pressure transmitting members disposed within said housing and adapted to fit around said pipe section, resilient sealing rings disposed within said housing and in alternate series with said pressure transmitting members, said sealing rings having outwardly pro- ,iecting rim sections, and means for moving said pressure transmitting members toward said head to cause the pressure transmitting members to press against said rim sections and deform the sealing rings and press their inner surfaces against the outer wall of the pipe section, said passageway communicatng with the outer surfaces of said sealing rings to transmit fluid pressure within said pipe section to said sealing rings an om to supplement the :pressure thereof against'i the outer wall of the pipe section.

' 6. A plug assembly for 'testingpipesnnder'fluid pressure comprisingia plugimember adaptedito fit within .a 'pipe section, -said:membershavingr:a

head and a passagewayopen; atzone'endzato fluid within said pipe section, an ..annulari pressure transmitting member disposedzaround saidzplug member and .adaptedrzto fitrwithin said pipesection; a resilientsealing ringzdi'sposed aroundsaid; j plug member and L between -saidlihead and: said pressure transmitting member, iland 'means ior moving said pressure transmittingzmerhber toward said I head'. to; deform thetsealing5ring mid press the outer? surtacezthereof agaiast' the .:in-

terior wall of the pipe-section; said :pa'ssageway communicating with the innersur-iace of the sealing ring to transmitfiuid-pressure within-the "pipe section to the sealing ring to supplement the pressure thereof against the interior'of -the pipe; i section.

7. A plug assembly for"testing pipes urider fluid pressure comprising-a plug member fora-pipe I section, said member havinga' head and aapassageway open at one end--to fiuid within-said? pipe section an-annular pressure transmitting member concentrically "disposed" relative'tosaid plug member, a resilient sealing ringdisposed-between said head and said 'pressuretransmitting membenandmeans for moving-said pressure. 1 transmitting member toward said-head-todeform the sealing ring and press one ofthe peri'pheral I surfaces thereof against-a wall of-said pipe section, sad passageway communicating withithe I other of said. peripheral-surfaces of saidsealing ring to transmit fluid pressure-within said pipe section to said sealing"ringito 'supplement the pressure thereof against. a -w'all" of .Zthe-s'aid pipe section.

8. A plug assembly 'ior testing pipes urider fluid 1 pressure comprising-a plug '"member a'dapte'd "to fit within a pipe section, said member having-a -head and apassageway' open atoneendto' fiuid "within said pipe section; an annulaz housing attached to said plug member atone -end and spaced therefrom throughout most ofits length,

said housing being provided with'a'separate-head, an inner annular pressuretransmitting member disposed around said plug member andadapted to fit within said pipe section, are'silient sealing ring havingran inwardlyprojec'ting 'rim section disposedaround saidplugmembergan outer 'annular ipressure transmitting member disposed within said housingand: adapted to' fit around saidpipe section, asresilient outer sealing ring havingan outwardly projecting rim section disposed within said housing, means for moving said inner. and outer pressure transmitting mem- V bers .toward said heads to cause the pressure membersto'pressagainstsaid ring sections and deform the sealing rings and press them against the interior and exterior walls of said pipe section, said passageway being adapted to transmit .fiuid' pressure within said pipe section to said sealing rings to supplement the pressure thereof against the walls of the pipe sectiomanda closel5 sage oi' fluid therethrough.

able openingin' said pipe member -for' the pas- 9. Aplug assembly for testing pipesunderfluid pressure comprising a plug member including-a housing having an open end adapted to fit around v anvend oi apipe section, said member having a nheadrat the open end and a passageway open-at 1' one endtofluid within said pipe section, an annular pressure transmitting member disposed within said housing-and adapted to'fit around said pipe section, a sealing ring'disposed within 5. said housing ancilbetweensaid' head'and said pressure transmitting member, andmeans for 1 moving said pressure transmitting member to- 'ward said head to deform the sealing ring and pl'ess its inner surface against theouter wall oi the pipe section, said passageway communicating with the outer surfaces of saidsealingringto transmit fluid pressure within-said pipe section to said sealing ring to supplement the pressure thereof against the outer wall ot said pipe-section.

JOHANN-HAHN.

REFERENCES' CITED The following references, are of record in, the

"file of this patent:

- UNITED STATES PATENTS 

